Preoperative prevalence of Barrett's esophagus in esophageal adenocarcinoma: a systematic review

The incidence of adenocarcinoma and squamous cell carcinoma of the esophagus: Barrett's esophagus makes a difference

BACKGROUND

Adenocarcinoma limited to the esophagus (ACE) arises in Barrett's esophagus (BE). The incidence of ACE is therefore restricted to this BE subpopulation, whose size is unknown and which is for 95% unidentified.

AIMS

To determine the age- and gender-specific incidence rates of ACE, limited to the BE subpopulation, within a defined geographical area and to compare them with those of squamous cell carcinoma of the esophagus (SCC), which can affect the entire population.

METHODS

The age- and gender-specific incidence rates for ACE and adenocarcinoma of the cardia (AGC) were calculated after an expert panel classified 87% of all cases of adenocarcinoma of the esophagus reported to the Danish Cancer Registry over a 6-yr period as ACE or AGC.

RESULTS

The age-specific incidence rates of ACE for males rose from 0.09/10(5) (30-34 yr) to 14.14/10(5) (80-84 yr), falling to 7.2/10(5) (85+ yr), for females from 0.19/10(5) (45-49 yr) to 2.79/10(5) (80-84 yr), falling to 2.43/10(5) (85+ yr) and yielding a gender ratio of 5.9:1; AGC demonstrated a similar pattern and a gender ratio of 4.26:1. However, the incidence rates of SCC continued rising after the age of 80 yr, with a gender ratio of 2.46:1.

CONCLUSIONS

The continuing rise in the SCC incidence rates in the elderly demonstrated that the unexpected decline and fall in the incidence rates of ACE over the age of 80 yr did not result from underdiagnosis but were most probably caused by a declining prevalence rate of BE, restricting the elderly BE subpopulation at risk of developing ACE.

Age and sex distribution of the prevalence of Barrett's esophagus found in a primary referral endoscopy center

BACKGROUND

Both the demographics underlying the sex ratio in the prevalence of Barrett's esophagus (BE) and the status of BE without intestinal metaplasia (IM) are unclear.

AIMS

To establish the demographics of histologically proven BE, IM+ and IM-, over a 15-yr period from a primary referral, endoscopy unit.

PATIENTS AND METHODS

For all BE patients aged 20-89 yr, identified between 1982 and 1996, IM+ or IM-, prevalences were calculated per 100 first endoscopies.

RESULTS

A total of 492 cases of BE, 320 (248 IM+) in males, 175 (127 IM+) in females were identified in 21,899 first endoscopies (10,939 males, 10,960 females). Between ages 20 and 59 yr in males and 20-79 in females, IM+, IM- and all BE prevalences rose by +/-7.36% for each additional year of age (p= 0.92) with, however, a 20-yr age shift between the sexes, resulting in a male:female OR 4.15 95% CI 2.99-5.77. A declining rate of increase in over 59 males resulted in an overall male:female OR 2.14, 95% CI 1.77-2.58. Over the age of 79 yr, BE prevalences/100 first endoscopies fell from a maximum of 5.1 in males and 3.65 in females to 3.38 and 2.53, respectively.

CONCLUSION

The 4:1 sex ratio and 20-yr age shift between males and females in the prevalence of BE, both IM+ and IM-, found in younger age groups, was the main cause of the overall BE 2:1 sex ratio. The very similar demographics of IM- and IM+ BE suggest they may be two consecutive stages in the same metaplastic process.

Pathogenesis of reflux esophagitis and Barrett's esophagus

An understanding of the pathogenesis of reflux esophagitis and Barrett's esophagus requires knowledge of the noxious elements in gastric juice and the three major esophageal defenses designed to protect against them. When the esophageal epithelium cannot prevent gastric acid from acidifying the intercellular spaces, the foundation is set for the development of the major symptoms, signs, and complications of reflux esophagitis. Inadequate defense by the epithelium can occur by exposure to the acidic refluxate for a prolonged period of time, because of defects in the antireflux or luminal clearance mechanisms, or by exposure to ingested products that directly impair the epithelium's intrinsic defenses, rendering it vulnerable to injury from even physiologic levels of acid reflux.

Present status of photodynamic therapy for high-grade dysplasia in Barrett's esophagus

GOALS

Review recent developments in Barrett's dysplasia including regulatory approval of porfimer sodium photodynamic therapy.

BACKGROUND

Barrett's esophagus is thought to be the result of long-standing gastroesophageal reflux disease and is known to be the most important risk factor for the development of esophageal adenocarcinoma. The natural history of Barrett's esophagus is not well known, but the annual incidence of invasive adenocarcinoma is estimated to be 0.5% (reported range, 0.2%-2.0%). This represents an increased risk for esophageal cancer of 30 to 60 times higher than normal subjects. As for colorectal cancer, malignant degeneration is Barrett's esophagus is thought to occur through a continuum of histologic stages: metaplasia, dysplasia and neoplasia. Barrett's high-grade dysplasia (formerly referred to as carcinoma in situ) is the histologic stage of disease that immediately precedes the development of invasive carcinoma.

CONCLUSIONS

Previously, Barrett's high-grade dysplasia patients were routinely referred for esophageal resection surgery based upon the assumption of inevitable progression to cancer, the high rate of undiagnosed synchronous cancers, and few treatment alternatives. Important developments in Barrett's high-grade dysplasia include recent publications regarding the natural history of Barrett's high-grade dysplasia and the regulatory approval for endoscopic ablation therapy using porfimer sodium photodynamic therapy (Photofrin PDT).

Epidemiologic risk factors for Barrett's esophagus and associated adenocarcinoma

The incidence of esophageal adenocarcinoma (AC) has increased dramatically in the Western world over the past 20 years and the majority of these cancers arise on the background of the preinvasive lesion Barrett's esophagus. The epidemiologic factors that contribute to an individual's susceptibility for Barrett's esophagus and associated cancer are likely to be multifactorial. However, the short time frame over which the incidence of adenocarcinoma has increased, and the increase across populations, provides a strong argument for environmental factors as etiologic agents, perhaps interacting with genetically determined characteristics that define personal susceptibility. In this review we discuss the epidemiologic evidence for the proposed demographic and environmental risk factors for the development of both Barrett's esophagus and AC. The current evidence suggests that significant risk factors include male sex, Caucasian race, and the presence of duodenogastroesophageal reflux disease. The susceptibility for reflux disease may in turn be influenced by factors such as obesity, the use of drugs that lower the lower-esophageal sphincter tone, and a protective effect of Helicobacter pylori colonization. There appears to be a weak association between smoking and AC. The role of dietary factors has not been studied adequately and deserves further attention. An understanding of the factors that predispose to the development and progression of Barrett's esophagus is crucial to the implementation of effective screening and prevention programs.

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Gene expression profiling in Barrett’s esophagus and cardia intestinal metaplasia: A comparative analysis using cDNA microarray

AIM: To study the difference of gene expression profile changes in Barrett’s esophagus (BE) and cardia intestinal metaplasia (CIM) and to screen the novel genes in the early stage by cDNA microarray.

METHODS: cDNA retrotranscribed from an equal amount of mRNA from BE and CIM epithelial tissues was labeled with Cy3 and Cy5 fluorescence as probes. The mixed probe was hybridized with three pieces of BiostarH-40 s double dot human whole gene chip. The chips were scanned with a ScanArray 4000. The acquired images were analyzed using GenePix Pro 3.0 software.

RESULTS: A total of 141 genes were screened out that exhibited different expression in all three chips. There were 74 upregulated and 67 downregulated genes in gene expression profiles of BE which were two times of that in CIM.

CONCLUSION: There is a difference in gene expression level between BE and CIM epithelia. These 141 genes probably relate to the occurrence and development of BE and the progression to adenocarcinoma.

Review article: what I do now to manage adenocarcinoma risk, and what I may be doing in 10 years' time

This article summarizes the present recommendations for the screening, surveillance and treatment of Barrett's oesophagus, and identifies those areas in which change seems likely within the next decade. As a result of economic constraints and emerging data on ethnic variations in the frequency of Barrett's oesophagus, future screening programmes will probably focus on those individuals most likely to develop Barrett's adenocarcinomas: older white men whose gastro-oesophageal reflux symptoms are of long duration. The present surveillance strategy for patients with Barrett's oesophagus relies heavily on random biopsy sampling of the oesophagus to find dysplasia. In the future, biomarkers other than dysplasia may be used to identify patients at high risk for carcinogenesis, and physicians may use endoscopic techniques, such as fluorescence spectroscopy, to identify areas of dysplasia for biopsy sampling. Indirect evidence suggests that super-aggressive antisecretory therapy and treatment with non-steroidal anti-inflammatory drugs may reduce the risk of cancer in Barrett's oesophagus. Well-designed prospective studies will be needed to determine whether these treatments have sufficient efficacy in cancer prophylaxis to justify the large numbers needed to treat. Finally, recent data are reviewed, which suggest that the gastro-oesophageal junction is exposed repeatedly to concentrated acid and to potentially genotoxic concentrations of nitric oxide generated from dietary nitrate. Future studies on carcinogenesis in Barrett's oesophagus may well focus on the combined roles of nitric oxide and gastric acid.

DNA abnormalities as marker of risk for progression of Barrett's esophagus to adenocarcinoma: image cytometric DNA analysis in formalin-fixed tissues

OBJECTIVES

To examine DNA content abnormalities in patients with Barrett's esophagus (BE) who progress to esophageal adenocarcinoma, using image cytometric DNA analysis (ICDA) of formalin-fixed tissues.

METHODS

Studies were performed on archived biopsies of BE patients' undergoing endoscopic surveillance before developing adenocarcinoma. A comparison group consisted of BE patients' free of cancer during a follow-up period of over 9 yr. Tissue sections were analyzed for the degree of dysplasia and for DNA content abnormalities, using image cytometry. Additional patients were also analyzed in a cross-sectional study of 56 BE cases with and without dysplasia, including 12 cases of adenocarcinoma.

RESULTS

Five patients developed adenocarcinoma during follow-up and earlier biopsies obtained before cancer diagnosis showed specialized intestinal metaplasia (SIM) followed by low-grade dysplasia (LGD) in one, SIM followed by high-grade dysplasia (HGD) in one, LGD in two, and HGD in one case. All five showed some DNA abnormality at baseline or in interval biopsies. In the comparison group, five of seven patients showed normal diploid DNA at baseline and on follow-up biopsies. One patient initially had diploid DNA, but developed aneuploidy 11 yr later. Another case initially had aneuploidy, but was diploid on follow-up. Overall, DNA abnormalities were found in 13% of cases with SIM without dysplasia, 60% with LGD, 73% with HGD, and 100% with adenocarcinoma.

CONCLUSIONS

(i) Image cytometric DNA analysis is a useful method to examine DNA abnormalities in formalin-fixed tissues and may be more sensitive in predicting progression to adenocarcinoma than HGD. (ii) Histological dysplasia of any grade and DNA abnormalities, help identify BE patients at high risk for adenocarcinoma.

Review article: oesophago-gastric adenocarcinoma -- an epidemiological perspective

This article reviews the epidemiology of cancers arising in the distal oesophagus and proximal stomach, sometimes collectively termed oesophago-gastric junctional adenocarcinomas. The several complexities involved in defining this group of cancers are considered and the reported increasing trends in incidence are reviewed, together with the descriptive epidemiology. The rates of these cancers are increasing, but not as dramatically as sometimes reported. They are also more common in white males than in other ethnic groups or in females. Although several aetiological risk factors have been reported, the two most consistent are an elevated body mass index (obesity) and a history of gastro-oesophageal reflux disease. Reflux is also associated with Barrett's oesophagus, an important and increasingly diagnosed premalignant lesion. The rate of progression from Barrett's oesophagus to cancer is controversial, as is the cost-benefit balance of routine endoscopic surveillance of such patients. The development of molecular biomarkers to identify Barrett's oesophagus patients with high rates of malignant transformation would represent a significant advance.

Barrett esophagus: will effective treatment prevent the risk of progression to esophageal adenocarcinoma?

Barrett esophagus is a complication of long-standing gastroesophageal reflux disease (GERD) and is the well-recognized premalignant condition for the majority of esophageal and gastroesophageal junction adenocarcinomas. Although duration of gastroesophageal reflux (GER), male sex, and, possibly, a strong family history are directly related to risk of Barrett esophagus, the role of screening in those with GERD and surveillance in those with confirmed Barrett syndrome remains controversial. Acid suppression with proton pump inhibitor (PPI) therapy plays a pivotal role in the management of symptoms in persons with chronic GER and Barrett esophagus. Although there is no conclusive evidence for the role of PPIs in regression of Barrett epithelium or prevention of dysplasia, longer-term studies that titrate the dose to normalization of esophageal pH may proffer different data in the future. Although highly touted in the literature, surgical and endoscopic ablation therapies are limited by several factors, including high rates of symptom recurrence, persistently abnormal pH values, need for repeat surgery, and, in the case of endoscopic therapy, residual Barrett metaplasia that can progress to high-grade dysplasia or cancer. These invasive interventions should only be considered after consultation with a gastroenterologist. Cancer chemoprevention strategies are just emerging, and their roles as direct chemoprotectants remain to be determined.

Multiple management modalities in esophageal cancer: epidemiology, presentation and progression, work-up, and surgical approaches

Annually, approximately 13,200 people in the U.S. are diagnosed with esophageal cancer and 12,500 die of this malignancy. Of new cases, 9,900 occur in men and 3,300 occur in women. In part I of this two-part series, we explore the epidemiology, presentation and progression, work-up, and surgical approaches for esophageal cancer. In the 1960s, squamous cell cancers made up greater than 90% of all esophageal tumors. The incidence of esophageal adenocarcinomas has risen considerably over the past two decades, such that they are now more prevalent than squamous cell cancer in the western hemisphere. Despite advances in therapeutic modalities for this disease, half the patients are incurable at presentation, and overall survival after diagnosis is grim. Evolving knowledge regarding the etiology of esophageal carcinoma may lead to better preventive methods and treatment options for early stage superficial cancers of the esophagus. The use of endoscopic ultrasound and the developing role of positron emission tomography have led to better diagnostic accuracy in this disease. For years, the standard of care for esophageal cancer has been surgery; there are several variants of the surgical approach. We will discuss combined modality approaches in part II of this series.

Laryngopharyngeal reflux symptoms better predict the presence of esophageal adenocarcinoma than typical gastroesophageal reflux symptoms

OBJECTIVE

To determine whether the presence of laryngopharyngeal reflux symptoms is associated with the presence of esophageal adenocarcinoma (EAC).

BACKGROUND

Most patients diagnosed with EAC have incurable disease at the time of detection. The majority of these patients are unaware of the presence of Barrett's esophagus prior to cancer diagnosis and many do not report typical symptoms of gastroesophageal reflux disease (GERD). This suggests that the current GERD symptom-based screening paradigm may be inadequate. Data support a causal relation between complicated GERD and laryngopharyngeal reflux symptoms. We theorize that laryngopharyngeal reflux symptoms are not recognized expeditiously, resulting in chronic esophageal injury and an unrecognized progression of Barrett's esophagus to EAC.

METHODS

This is a case-comparison (control) study. Cases were patients diagnosed with EAC (n = 63) between 1997 and 2002. Three comparison groups were selected: 1) Barrett's esophagus patients without dysplasia (n = 50), 2) GERD patients without Barrett's esophagus (n = 50), and 3) patients with no history of GERD symptoms or antisecretory medication use (n = 56). The risk factors evaluated included demographics, medical history, lifestyle variables, and laryngopharyngeal reflux symptoms. Typical GERD symptoms and antisecretory medication use were recorded. Multivariate analysis of demographics, comorbid risk factors, and symptoms was performed with logistic regression to provide odds ratios for the probability of EAC diagnosis.

RESULTS

The prevalence of patients with laryngopharyngeal reflux symptoms was significantly greater in the cases than comparison groups (P = 0.0005). The prevalence of laryngopharyngeal reflux symptoms increased as disease severity progressed from the non-GERD comparison group (19.6%) to GERD (26%), Barrett's esophagus (40%), and EAC patients (54%). Symptoms of GERD were less prevalent in cases (43%) when compared with Barrett's esophagus (66%) and GERD (86%) control groups (P < 0.001). Twenty-seven percent (17 of 63) of EAC patients never had GERD or laryngopharyngeal reflux symptoms. Fifty-seven percent of EAC patients presented without ever having typical GERD symptoms. Chronic cough, diabetes, and age emerged as independent risk factors for the development of EAC.

CONCLUSIONS

Symptoms of laryngopharyngeal reflux are more prevalent in patients with EAC than typical GERD symptoms and may represent the only sign of disease. Chronic cough is an independent risk factor associated with the presence of EAC. Addition of laryngopharyngeal reflux symptoms to the current Barrett's screening guidelines is warranted.

Barrett's esophagus: management of high-grade dysplasia and cancer

Esophagectomy remains the treatment of choice for the appropriate patient with Barrett's adenocarcinoma invading beyond the mucosa, without evidence of distant metastasis or invasion of adjacent organs. On the other hand, therapeutic management of patients with Barrett's high-grade dysplasia (HGD) or mucosal adenocarcinoma should be individualized, taking into account the patient's preferences, willingness to return for frequent endoscopic biopsies, and medical fitness to undergo esophagectomy. Surgery has to be considered the best treatment for HGD or superficial carcinoma, unless contraindicated by severe comorbidities, because it has proven to be the only treatment that is successful in curing the condition and preventing recurrent HGD or the development of invasive cancer. Nonsurgical treatment by photodynamic therapy or endoscopic mucosal resection may be a less invasive and organ-sparing option for elderly, poor-risk patients but it is still to be considered an investigational therapy that should only be conducted under a clinical trial protocol. Finally, intensive endoscopic biopsy surveillance of patients with HGD is another investigational option that may allow prompt treatment of cancer if it develops. However, few data document the safety of this observational approach.

Biomarkers of esophageal adenocarcinoma and Barrett's esophagus

The rising incidence and poor prognosis of esophageal adenocarcinoma in the Western world have intensified research efforts into earlier methods of detection of this disease and its relationship to Barrett's esophagus. The progression of Barrett's esophagus to adenocarcinoma has been the focus of particular scrutiny, and a number of potential tissue and serum-based disease biomarkers have emerged. The epidemiology and pathogenesis of esophageal adenocarcinoma are outlined. Tissue biomarkers allowing risk stratification of Barrett's are reviewed as well as strategies currently being used to discover novel biomarkers that will facilitate the early detection of esophageal adenocarcinoma. Finally, the uses of biomarkers as predictive tests for targeted treatments and as surrogate endpoints in chemoprevention trials are considered.

Review article: screening and surveillance of Barrett's oesophagus: what is a cost-effective framework?

There is a strong association between symptomatic gastro-oesophageal reflux and oesophageal adenocarcinoma. With this in mind, the American College of Gastroenterology has recently revised its practice guidelines for the screening of patients with chronic gastro-oesophageal reflux disease (GERD) to identify those at risk of oesophageal adenocarcinoma, and recommends surveillance to identify curable oesophageal neoplasms in patients with established Barrett's oesophagus. Patients with chronic GERD symptoms, particularly those aged over 50 years, should undergo upper endoscopy. Patients found to have Barrett's oesophagus should be treated with acid suppression for GERD symptoms and then undergo regular surveillance endoscopy. Surveillance endoscopy every 3 years is recommended for those without dysplasia. For patients with verified low-grade dysplasia, yearly surveillance endoscopy is recommended. For those with focal high-grade dysplasia (defined as high-grade dysplastic changes involving fewer than five crypts), the condition may be followed with endoscopic surveillance performed at 3-month intervals. If there is verified, multifocal high-grade dysplasia, intervention (e.g. oesophagectomy) may be considered. Both observational and computer models suggest a benefit associated with screening and surveillance. Endoscopic screening and surveillance for Barrett's oesophagus compares favourably with mammography for the detection of breast cancer and other accepted medical practices.

Screening for Barrett's esophagus in colonoscopy patients with and without heartburn

BACKGROUND & AIMS

The population prevalence of Barrett's esophagus (BE) is uncertain. Our aim was to describe the prevalence of BE in a volunteer population.

METHODS

Upper endoscopy (EGD) was performed in 961 persons with no prior history of EGD who were scheduled for colonoscopy. Symptom questionnaires were completed prior to endoscopy. Biopsy specimens were taken from the gastric cardia and any columnar mucosa extending > or =5 mm into the tubular esophagus and from the stomach for H. pylori infection in the last 812 patients.

RESULTS

The study sample was biased toward persons undergoing colonoscopy, males, and persons with upper GI symptoms. The prevalence of BE was 65 of 961 (6.8%) patients, including 12 (1.2%) with long-segment BE (LSBE). Among 556 subjects who had never had heartburn, the prevalences of BE and LSBE were 5.6% and 0.36%, respectively. Among 384 subjects with a history of any heartburn, the prevalences of BE and LSBE were 8.3% and 2.6%, respectively. In a univariate analysis, LSBE was more common in those with any heartburn vs. those with no heartburn (P = 0.01), but the sample size was insufficient to allow multivariate analysis of predictors of LSBE. In a multivariate analysis, BE was associated with increasing age (P = 0.02), white race (P = 0.03), and negative H. pylori status (P = 0.04). Overall, BE was not associated with heartburn, although heartburn was more common in persons with LSBE or circumferential short segments.

CONCLUSIONS

LSBE is very uncommon in patients who have no history of heartburn. SSBE is relatively common in persons age > or =40 years with no prior endoscopy, irrespective of heartburn history.

Section I: epidemiological review

The incidence of esophageal adenocarcinoma has increased tremendously in the United States and other Western countries over the past 30 years while the incidence of esophageal squamous cell carcinoma has remained unchanged. The rate of increase in incidence is higher than for any other cancer. The reasons for this are multifactorial. Despite this, esophageal cancer remains a relatively uncommon malignancy. Barrett's esophagus (BE) is the most important risk factor for the development of esophageal adenocarcinoma and is believed to be the precursor lesion for most. The risk of developing esophageal adenocarcinoma from known BE is estimated to be 0.5% per patient year. Persistent high-grade dysplasia in BE is a sensitive indicator for the development of esophageal adenocarcinoma. However, only a minority of patients with BE are ever diagnosed and, therefore, surveillance endoscopy in Barrett's patients has failed to affect the incidence of esophageal adenocarcinoma. The relationship of Helicobacter pylori to esophageal adenocarcinoma is complex, but nonsteroidal antiinflammatory drugs may confer protection against the development of this cancer. Fortunately, improved survival is being seen with both squamous cell esophageal carcinoma and esophageal adenocarcinoma. Additional study is required to better determine the risk factors for the development of esophageal cancer, and epidemiologic understanding will prove important in developing methods of detection and therapeutic intervention for this disease.

Autofluorescence endoscopy for detection of high-grade dysplasia in short-segment Barrett's esophagus

BACKGROUND

The occurrence of precancerous lesions, such as high-grade dysplasia, in patients with short-segment Barrett's esophagus is controversial. This study assessed the efficacy of autofluorescence endoscopy for detection of high-grade dysplasia in short-segment Barrett's esophagus.

METHODS

A total of 34 patients (28 men, 6 women; age range 40-77 years) with histopathologically proven short-segment Barrett's esophagus were studied. Autofluorescence endoscopy was performed by using monochromatized blue light (425-455 nm) filtered from a conventional xenon light source. A total of 136 and 109 biopsy specimens were taken from Barrett's mucosa under control, respectively, white light endoscopy and autofluorescence endoscopy.

RESULTS

High-grade dysplasia was found in 9 (8.3%) autofluorescence-guided biopsy specimens, which was significantly greater than the number of white light endoscopy-guided biopsy specimens with this finding (one positive biopsy specimen, 0.7% of total biopsy specimens obtained). Autofluorescence endoscopy detected high-grade dysplasia in 7 patients, 6 more than were identified with white light endoscopy. In the one patient with high-grade dysplasia detected by white light endoscopy-guided biopsy specimens, autofluorescence-guided biopsy specimens revealed only low-grade dysplasia.

CONCLUSION

Autofluorescence endoscopy in patients with short-segment Barrett's esophagus increases the detection rate of high-grade dysplasia.

Clinical Manifestations and Esophageal Complications of GERD

This report focuses on the manifestations of gastroesophageal reflux disease (GERD) that are caused directly by contact between refluxed gastric juice and the esophageal mucosa. These manifestations include heartburn, peptic esophageal erosion and ulceration, peptic esophageal stricture, and Barrett esophagus. Peptic esophageal erosions and ulcerations are excavated defects in the esophageal mucosa that result when epithelial cells succumb to the caustic effects of refluxed acid and pepsin. Uncommonly, esophageal ulcers are complicated by hemorrhage, perforation, and penetration into the airway. Esophageal ulcers can stimulate fibrous tissue production and collagen deposition that result in stricture formation, and the ulcers can heal through a metaplastic process in which an intestinal-type epithelium replaces the damaged squamous cells (Barrett esophagus). The management of these conditions is discussed below.

Is neoadjuvant therapy the answer to adenocarcinoma of the esophagus?

The conflicting results of randomized studies have led to confusion over the proper management of patients with esophageal adenocarcinoma. Although there is no firm evidence that neoadjuvant chemoradiation improves survival, because of the shortcomings of these trials, this method of treatment is practiced at many centers. Without the results of another multiinstitutional randomized trial, the true answer may never be known.

Long-term endoscopic surveillance of patients with Barrett's esophagus. Incidence of dysplasia and adenocarcinoma: a prospective study

OBJECTIVE

Barrett's esophagus (BE) is a premalignant condition for which regular endoscopic follow-up is usually advised. We evaluated the incidence of esophageal adenocarcinoma (AC) in patients with BE and the impact of endoscopic surveillance on mortality from AC.

METHODS

A cohort of newly diagnosed BE patients was studied prospectively. Endoscopic and histological surveillance was recommended every 2 yr. Follow-up status was determined from hospital and registry office records and telephone calls to the patients.

RESULTS

From 1987 to 1997, BE was diagnosed in 177 patients. We excluded three with high-grade dysplasia (HGD) at the time of enrollment. Follow-up was complete in 166 patients (135 male, 31 female). The mean length of endoscopic follow-up was 5.5 yr (range 0.5-13.3). Low-grade dysplasia (LGD) was present initially in 16 patients (9.6%) and found during follow-up in another 24 patients. However, in 75% of cases, LGD was not confirmed on later biopsies. HGD was found during surveillance in three patients (1.8%), one with simultaneous AC; two with HGD developed AC later. AC was detected in five male patients during surveillance. The incidence of AC was 1/220 (5/1100) patient-years of total follow-up, or 1/183.6 (5/918) patient-years in subjects undergoing endoscopy. Four AC patients died, and one was alive with advanced-stage tumor. The mean number of endoscopies performed for surveillance, rather than for symptoms, was 2.4 (range 1-10) per patient. During the follow-up years the cohort had a total of 528 examinations and more than 4000 biopsies.

CONCLUSIONS

The incidence of AC in BE is low, confirming recent data from the literature reporting an overestimation of cancer risk in these patients. In our patient cohort, surveillance involved a large expenditure of effort but did not prevent any cancer deaths. The benefit of surveillance remains uncertain.

Reflux, Barrett's oesophagus and adenocarcinoma: burning questions

The incidence of oesophageal adenocarcinoma is increasing rapidly in Western populations. Gastro-oesophageal reflux disease is a strong risk factor for both this tumour and the pre-cancerous lesion Barrett's oesophagus, but the underlying disease mechanisms remain unclear. Developing a better understanding of the aetiology and pathogenesis of Barrett's oesophagus, including the induction of DNA damage and genetic alterations, might provide opportunities for improved management of individuals with this disease. This could include a better rationale for screening and surveillance programmes, as well as targeted intervention strategies.

Barrett esophagus

PURPOSE

The importance of an in-depth understanding about Barrett esophagus is ultimately to decrease the mortality and morbidity from esophageal adenocarcinoma cancer by early detection of metaplasia and dysplasia and appropriate therapy. This review summarizes several publications in the past year related to the epidemiology, pathogenesis, screening and surveillance, new methods for detection of metaplasia/dysplasia, and advances in the treatment of Barrett esophagus.

RECENT FINDINGS

Patients with Barrett esophagus are characterized by the presence of risk factors usually indicative of severe types of gastroesophageal reflux disease. Recent insights into epidemiology and pathogenesis have shown that the risk of high-grade dysplasia and adenocarcinoma may be related to the increasing length of Barrett esophagus, size of hiatus hernia, and severity of acid reflux. The role of smoking and alcohol consumption remains controversial. Increasing the number of biopsies by repeat standard endoscopy can enhance the yield of intestinal metaplasia in patients with suspected short-segment Barrett esophagus. Costs of surveillance using standard endoscopy and random biopsies would be very high and using special techniques to target specific areas could ultimately help in cost reduction. Emerging data on new techniques and technology such as vital staining with methylene blue and protoporphyrin fluorescence can increase the yield of metaplasia and dysplasia. Biomarkers studies have revealed that p53 mutation by the loss of heterozygosity can help detect patients with low and high risk for cancer progression. Studies thus far have been unclear whether acid suppression alone can impact the malignant progression in Barrett esophagus patients. Inhibition of cyclooxygenase by aspirin or nonsteroidal anti-inflammatory drugs may be a promising chemoprevention strategy against dysplasia and esophageal adenocarcinoma development as shown in some recent studies. Nonsurgical treatment by photodynamic therapy or mucosal resection may be a less invasive and organ-sparing option for some patients with high-grade dysplasia and early adenocarcinoma.

SUMMARY

In the past year we have made major strides in our knowledge of this premalignant lesion. Recent studies have shed light in a better understanding of the epidemiology of Barrett esophagus, including clinical and endoscopic factors associated with high-grade dysplasia or esophageal adenocarcinoma and various biomarkers that would identify patient subsets with low and high risk for cancer progression. This will eventually have significant implications on the screening, surveillance, and treatment of the disease. Advanced endoscopic therapies including mucosectomy or photodynamic therapy may be emerging options in patients with intraepithelial neoplasia.

Barrett's esophagus: an update

Barrett's esophagus (BE) is a complication observed in a small subset of patients with chronic gastroesophageal reflux. It is characterized by the presence of intestinal-type goblet cells in biopsies from the lower esophagus. The prevalence of BE increases with age, affecting 1% of the population older than 60 years. A genetic predisposition to reflux disease has been proposed. In a twin study of reflux disease, concordance was greater in monozygotic than dizygotic twins. An association between BE and esophageal adenocarcinoma, the incidence of which has increased remarkably in the last few decades, has been established. Esophagogastric junction cancers can arise from small areas of cardia intestinal metaplasia (CIM). Regular endoscopic and histologic follow-up of BE patients is recommended. Surveillance of patients with CIM is not advised. Chromoendoscopy may help to detect areas of high-grade dysplasia (HGD). The ablation of BE, e.g. by PDT or argon plasma coagulation, is not yet proven to reduce the cancer risk. Esophagectomy is still the standard management of HGD. Endoscopic mucosal resection may be used for visible, localized lesions with HGD, and this technique may be combined with thermal ablation for areas of HGD without visible abnormality.

The pathogenesis of Barrett's esophagus

Significant progress has been made in clinicians' understanding of the molecular pathogenesis of BE, and the laboratory findings are beginning to lead to hypothesis-driven clinical studies; however, the following questions remain unanswered: (1) how can clinicians identify the persons most at risk for the development of esophageal adenocarcinoma, (2) what are the environmental gene interactions in esophageal carcinogenesis, and (3) can clinicians prevent the development of esophageal adenocarcinoma in the population at risk? As esophageal adenocarcinoma starts to reach epidemic proportions, further research in these areas is urgently required. With the advent of the genomic era and an explosion in studies in BE, significant progress can be made.

Oesophageal disorders: future developments

Elicitation of the characteristic symptom patterns remains the primary approach to the diagnosis of gastro-oesophageal reflux disease, and this may be enhanced by developments in the use of high-resolution endoscopy and oesophageal biopsy. For future therapy, proton pump inhibitors and anti-reflux surgery may compete with reversible acid pump blockers, reflux inhibitor drugs and diverse luminally delivered physical anti-reflux therapies. Short-segment Barrett's oesophagus is known to be highly prevalent, but its impact on the risk of adenocarcinoma remains poorly defined. Biomarkers for Barrett's oesophagus have been proposed to aid in the stratification of cancer risk, and cytology may assume more importance in the future. Endoscopic surveillance for Barrett's oesophagus is widely practised, but more data are needed to demonstrate cost-effectiveness and a positive impact on mortality. Animal and limited human studies suggest that chemoprevention may become an important strategy in reducing the risk of adenocarcinoma. The ablation of Barrett's epithelium results in a reversal of Barrett's epithelium, albeit with an uncertain long-term outcome.

Screening for esophageal adenocarcinoma: an evidence-based approach

Adenocarcinoma of the esophagus and the gastroesophageal junction is the twentieth most common malignancy in the United States. In developed countries, the incidence of esophageal adenocarcinoma is increasing 5% to 10% per year. Despite the use of endoscopy for earlier detection, mortality from esophageal adenocarcinoma has not declined. Using an evidence-based approach, we review screening methods for esophageal adenocarcinoma, including the use of a symptom questionnaire, identification of patients with a family history of Barrett's esophagus, peroral or transnasal endoscopy, barium swallow, fecal occult blood testing, and brush and balloon cytology. Screening has not been shown to reduce rate of progression of Barrett's esophagus to esophageal cancer. Many treatment options for dysplastic Barrett's esophagus or early carcinoma appear effective, but long-term follow-up data are not available. There is currently insufficient evidence supporting population-based screening for Barrett's esophagus. Several risk factors, including severe reflux symptoms, male sex, and obesity, may identify patients with gastroesophageal reflux disease who are at the greatest risk of the development of cancer.

Barrett's esophagus: clinical characteristics

Barrett's metaplasia develops in 6-14% of individuals with gastroesophageal reflux. Barrett's adenocarcinomas are increasing in epidemic proportions for as yet unknown reasons, approximately 0.5-1% of patients with Barrett's will develop adenocarcinoma. Heartburn duration and frequency (but not severity), male gender, and Caucasian race are major risk factors for developing cancer. Obesity and smoking are weak risk factors. Survival is determined by depth of tumor invasion (stage). Once invasion of the muscularis propia occurs, the vast majority of patients will have developed widespread metastasis, even when clinical staging studies are negative. No currently available therapy results in prolonged survival once metastases develop. Thus, the more widespread use of effective surveillance strategies is the only currently available means for reducing the morbidity and mortality associated with Barrett's adenocarcinoma.